Parents' Smoking Gives Children Asthma, Wheezing

Dec. 2, 1999 (Atlanta) -- The largest study of its kind confirms earlier reports: parents who smoke greatly increase their children's risk of asthma and wheezing.

"There is no question that a parent who smokes -- especially a mother -- puts her child at risk of asthma," Norman H. Edelman, MD, tells WebMD in an interview seeking objective commentary. Edelman serves as consultant for scientific affairs to the American Lung Association.

The study collected data on almost 19,000 children aged 6 and 7 and on more than 21,000 adolescents aged 13 and 14. Its findings show that in Italy -- where at least one parent smokes in more than half of all families -- a large proportion of children and adolescents can lay the blame for their asthma and wheezing directly on their parents' smoking.

"We estimated that 15% ... of the current asthma cases among children and 11% ... of the current wheezing cases among adolescents are attributable to parental smoking in Italy," say Nera Agabiti and colleagues with the internationally regarded group of epidemiologists known as the SIDRIA Collaborative Group. The group published their findings in the November issue of the journal Epidemiology.

The link between parents who smoke and children with asthmatic disease is by no means unique to Europe. They echo the results of a 1997 report by the California Environmental Protection Agency (EPA), which estimated that parents who smoke each year cause 8,000 to 26,000 new cases of childhood asthma in the U.S. and make existing asthma worse in 20% of the 2 million to 5 million children who already have the disease.

The percentage of actual asthma cases in the U.S. caused by parental smoking is smaller than that seen in Italy only because a smaller percentage of U.S. adults are smokers. "In the U.S., the attributable risk would be lower because the prevalence of smoking is lower," Michael Lipsett, MD, lead author of the respiratory disease section of the California EPA report, tells WebMD.

But Lipsett, now affiliated with the University of California, San Francisco, notes that the risk posed to children by even one household smoker was the same in the large Italian study as it was in the analysis of numerous smaller U.S. studies reported in the California EPA report.